Spiral spring construction



Oct. 16, 1956 G. E. TAYLOR 2,766,933

SPIRAL SPRING CONSTRUCTION Filed June 11, 19 53 .[nvenfor Geolgge f. Tag/01 United States Patent SPIRAL SPRING CONSTRUCTION George E. Taylor, Chicago, Ill. Application June 11, 1958, Serial No. 360,989

3 Claims. (Cl. 267-1) This invention relates to spiral springs, and articularly to such springs of the type that are ordinarily used in bed springs and mattresses and various kinds of upholstered furniture.

Springs of the aforesaid character have reached an extremely high state of commercial development, and are produced in large numbers in substantially uniform sizes and constructions. Basically, these springs embody a multiple coil spiral arrangement, with the coils varying in diameter from the center of the spring toward opposite ends thereof so that the central coil or coils of the springs are the smallest and the end coils are the largest, and the free end of the spring wire that forms the end or terminal coil at each end of the spring is coiled about an intermediate anchoring portion of the spring wire to afford a knot, which theoretically is intended to maintain the end coil at a constant size or diameter. This coiled knot is relatively tight upon the anchoring portion of the wire, and this anchoring portion, in many instances, has a lateral offset formed therein to cooperate with the coiled knot in preventing undesired endwise slipping of the knot along the anchoring portion when the spring is subjected to load. The attainment of a fixed location of the knot on the anchoring portion of the spring wire has been found to be extremely difficult, and even Where an offset arrangement has been formed on the anchoring portion, it has been found that due to machine wear, or variation of the adjustments in the spring forming machine, the coiled knot, in many instances, has a tendency to slip along the anchoring portion of the spring wire, thus to cause the diameter of the end coil of the spring to change in an undesired manner.

in view of the foregoing, it is the primary object of the present invention to enable the position of the knot in such a spring to be permanently fixed with relation to the anchoring portion of the spring, and a related object is to enable this to be accomplished in a simple and inexpensive manner that may readily be coordinated with the usual method of spring manufacture.

More specifically, it is an object of the present invention to permanently unite the knots in such springs with the anchoring portions of the springs by welding, and to accomplish a mechanical interlock as an incident to the performance of the welding operation.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawing which, by way of illustration, shows a preferred embodiment of the present invention and the principles thereof and what I now consider to be the best mode in which I have contemplated applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

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In the drawings:

Fig. 1 is a perspective view of a spring embodying the features of the invention;

Fig. 2 is an enlarged fragmental plan view showing the welded knot construction of the present invention; and

Figs. 3 and 4 are cross sectional views taken substantially and respectively along the lines 33 and 44 of Fig. 2.

For purposes of disclosure, the invention is herein illustrated as embodied in a coil spring 10 mad from spring wire of round cross section and fonrned to a double conical spiral form that affords a central coil 11 that is relatively small, and other coils 12 on opposite ends of the central coil 11 and of a somewhat larger diameter. The coils 12 continue into what may be termed anchoring portions 12A, and the final or end coils 13 extend from this anchoring portion 2A at a larger dia ieter and terminate in arms 13A that extend at an angle from the main portion of the coil 13A at substantially the location of the anchoring portions 12A. The ends of the arm 13A are utilized to form spirally coiled knots that are wound around the anchorin portion 12A in a relatively tight coiled relationship. T his tightly coiled relationship, coupled in some instances with a lateral offset in the anchorin portion 12A, have in the past een relied upon to prevent undesired endwise displace ment of the knot 14 along the anchoring portion 12A, but due to variations in the spring Wire stock, variations in machine adjustment and progressive wear of the machine parts, it is found that this desired fined relationship of the knot 14 on the anchoring portion 12A not uniformly attained.

Under and in accordance with the present invcnon, the knot 14 is maintained in this desired fixed relationship on the anchoring portion 12A by weldir of the knot 14 to the anchoring portion 12A. This wcidi' ation is performed by spot welding, wherein the trodes of the welding apparatus are PTCSSod firmly on opposite sides of the knot it. Because of the pressure ti thus applied, it is found that the knot 14 has the elements thereof flattened as at 14F, Figs, 3 and 4, and the surfaces of the anchoring portion 12A are also flattened in a complementary and interlocked manner, as indicated at 12F in Figs. 3 and 4-. As a result of this mechanical interlock, and by reason of the welding of these mechanically interlocked surfaces together, it i found that the normal forces that are applied to a spri such as the spring 10 do not cause displacement of knot 14 along the anchoring portion 12A. This desirable result is attained even in those instances where variations in the spring wire or in machine adjustment or wear have caused the knot 14 to be relatively loose. This, therefore, acts to overcome deficiencies that have heretofore been present in springs of the aforesaid c acter. Any undesired effect of the welding opera..on upon the temper of the spring wire is, of course, overcome in the usual heat treating operation that is applied to springs of the aforesaid character.

From the foregoing description, it will apparent that the present invention affords a spiral spring construction adapted for use in upholstered cushions, bed springs and the like, wherein uniformity of size of the end coils of the springs is preserved in ever, This, of course, renders the springs more various kinds of upholstery and bed spring E results in continued uniformity of the spri 3 supported surfaces that are produced by the use of springs made under the present invention.

Thus, while I have illustrated and described the preferred embodiment of my invention, it is to be understood that this is capable of variation and modification,

and I therefore do not Wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. A multiple coil spiral spring formed from spring wire to afford a plurality of coils terminating in end coils having free ends, such free ends being wound about anchoring portions of the spring Wire to afford knots for determining and maintaining the diameter of the end coils, said knots being fixed to said anchoring portions by spot welding to afford mechanically interlocking flat faces between the knots and said anchoring portions.

2. A multiple coil spiral spring formed from spring wire of round cross section to afiord a plurality of coils terminating in end coils having free ends, such free ends being Wound about anchoring portions of the spring wire to afford knots for determining and maintaining the diameer of tr e end coils, said knots being fixed to said anchoring portions by spot Welding to form flat engaged and Welded surfaces on the round wire of said knots and said anchoring portions.

3. A spring for beds, upholstered furniture and like uses comprising a continuous wire wound spirally in opposite directions around a connnon axis and from a common vertex to form a double cone spring, the opposite end portions of the wire each being extensions of the opposite spirals that constitute the bases of the respective cones, and the ends of the wire at such extensions each being wrapped about a portion of the spiral adjacent thereto and then spot welded to the portion of such adjacent spiral to afiord mechanically interlocking flat faces between such ends and portions of the spiral allocated thereto.

References Cited in the file of this patent UNITED STATES PATENTS 195,676 Turner Sept. 25, 1877 1,756,669 Stubnitz Apr. 29, 1930 2,137,718 Friberg Nov. 22, 1938 2,200,942 Wesley May 14, 1940 2,249,999 Asaro July 22, 1941 2,516,566 Hager July 25, 1950 2,611,910 Bell Sept, 30, 1952 2,641,758 Levine June 9, 1953 FOREIGN PATENTS 578,530 Great Britain July 2, 1946 427,991 France Aug. 19, 1911 

